In the operation of medical devices, especially of diagnostic and intervention systems in angiography, cardiology or neurology, the very widest range of operating units are used for control of components of the respective medical device. A safety-relevant action of the devices is to be seen here for example as an action such as one in which a patient or the operating personnel of the device can come to harm indirectly or directly.
A movable component of a medical device to be controlled is for example the C-arm which serves as a carrier for imaging components, for X-ray devices for example. Specifically in the operation of medical devices in which such a movable component has to be positioned in respect of a person, it is important that a hardware error does not lead to incorrect behavior of the movable components. In the worst case the patient can be seriously injured by an inadvertent, uncontrolled or automatic movement of such a movable component.
But even operation of components and functional units which do not directly result in adverse effects on the patient from movements of components should if possible be able to be executed so that errors are avoided. Such a functional unit would for example be a detector system or a radiation collimator, wherein an inadvertent repositioning of imaging components could prevent use of image data obtained. The examination would therefore have to be repeated and the patient subjected to renewed irradiation for example. A further functional unit would be provided for example by an on switch for x-radiation, wherein incorrect operation can likewise cause injury to a patient.
Furthermore it is helpful for the operator of a medical device to obtain haptic feedback through the operating unit, even through sterile coverings or gloves, about a successful device operation performed. Since the primary attention of the operator of a medical device for diagnosis and/or intervention is devoted as a rule to a patient or to the examination results obtained, the necessity to visually check the operating unit is disruptive and is designed to be largely avoided through the haptic feedback.
Previously the interfaces between medical devices, especially of diagnosis and intervention systems in angiography, cardiology and neurology and the operators, were implemented by means of sensors, which usually possess two mechanically-coupled contacts which can both be interrogated. This reveals a failure of one of the contacts if necessary, makes possible the diagnostic establishment of an error and prevents an inadvertent and unchecked action of the medical device.
Sensors in combination with a liquid crystal display are already known from DE 101 51 236 A1 for medical devices, which as well as allowing operation, simultaneously make it possible to display information.
In recent years touch-sensitive input fields have been developed which are also known by the names touchscreen touchpad, sensor screen and the like. These involve an operating unit for a processing unit in which, by touching selected areas of the screen, a program sequence on the processing unit can be influenced. The image in this case can be generated either dynamically by means of displays, monitors or via a projection or alternatively also by a static, for example printed, image. Such an input field can have a single or a plurality of touch-sensitive areas able to be actuated independently of one another.
A touchscreen is known from U.S. Pat. No. 6,504,530, which has a number of touch-sensitive input fields. These can for example be used in combination with a liquid crystal display or a cathode-ray tube to generate image information to be selected by touch. In this case a touch, which is detected by means of a first touch-sensitive input field, can be confirmed by a second touch-sensitive input field, which preferably is of another type or operates in a different way. Incorrect operation or unintentional operation is largely prevented by this.
For operation of safety-relevant device functions of medical devices which can have negative effects on a patient and/or on the operating personnel, touch-sensitive input fields have not previously been used, since these do not fulfill the requirements for fault tolerance and/or sufficient haptic feedback.